Q 12-12-014NEETJEE MainMedium
The speed of the electron in the first Bohr orbit of hydrogen is about $2.2 \times 10^6$ m/s. Its speed in the third orbit of doubly ionised lithium ($Z = 3$) is
Answer: (C) $2.2 \times 10^6$ m/s
$v_n \propto \dfrac{Z}{n}$: $\dfrac{3}{3} = 1$, so the speed is the same as in hydrogen's first orbit.
Solution by Sreeraj P, M.Sc Physics